Research And Development Of Renewable Nano-cellulose High-performance Antibacterial Material And Its Application As A New Protective Mask

Bacterial cellulose（BC）has high water absorption,high water holding capacity and high mechanical strength due to its unique network structure.BC contains a large number of hydroxyl functional groups,which makes it biocompatible and provides unique conditions for its modification.As an ideal biomedical material,BC is limited by its application in the field of biomedicine because BC does not have bacteriostatic properties.Therefore,the composite preparation of BC functional composite materials by compounding BC with other bacteriostatic materials is one of the most effective solutions to achieve BC with bacteriostatic properties.In this thesis,BC was prepared by static culture and CeO₂ NPs,BC@CeO₂ NPs,nonwovens@BC@CeO₂ NPs and cotton@BC@CeO₂ NPs composites were prepared by microwave-assisted synthesis.The morphology and structure of CeO₂ NPs and composites were characterized by various characterization methods such as ultraviolet spectrophotometer（UV-Vis）,particle size&potential analyzer（Zeta&DLS）,scanning electron microscope（SEM）,high-resolution transmission electron microscopy（TEM）,thermogravimetric analyzer（TGA）,X-ray diffractometer（XRD）,etc.At the same time,the antibacterial activities of CeO₂NPs and different composites against Escherichia coli,Staphylococcus aureus and Pseudomonas aeruginosa were also explored.Finally,the composite material is applied to mask materials as a new bacteriostatic composite material.The specific research content of this thesis is as follows:（1）BC was prepared by static culture,CeO₂ NPs and BC@CeO₂ NPs composites were prepared by microwave-assisted synthesis.The influence of synthesis conditions such as time,temperature,speed,power,magneton size and other conditions on microwave-assisted synthesis was studied.The results showed that the optimal synthesis conditions for CeO₂ NPs were 150°C,3（reaction time）-1 min（heating time）,200 rpm,850 W,and small magnetons.Through the characterization results of CeO₂ NPs,it can be seen that the CeO₂ NPs prepared by microwave-assisted synthesis have a cubic fluorite structure,and the uniform nanoparticle size is 5±1 nm.Through the characterization results of BC@CeO₂ NPs composites,it can be seen that BC@CeO₂ NPs composites were successfully prepared by microwave-assisted synthesis,with good stability and CeO₂ NPs loading of about 17%.By changing the amount of microwave reaction solution,the loading of CeO₂ NPs on BC can be effectively controlled.A variety of antibacterial test results showed that CeO₂ NPs and BC@CeO₂ NPs composites could effectively inhibit the growth of bacteria,and the antibacterial rate was as high as 98%.（2）The non-woven@BC,cotton cloth@BC composites were prepared by static culture method,and the results showed that the non-woven@BC,cotton cloth@BC composites prepared during standing culture for 12 h were used for follow-up research without affecting the properties of the non-woven fabric and cotton fabric.Non-woven fabrics@BC@CeO₂NPs,cotton fabrics@BC@CeO₂ NPs composites were prepared by microwave-assisted synthesis.Through the characterization results,it can be seen that the composites prepared by microwave method have higher stability.The antibacterial experimental results showed that the composite material had an inhibitory rate of 98%against Escherichia coli,Staphylococcus aureus and Pseudomonas aeruginosa,which could effectively inhibit the growth of bacteria.Non-woven composite materials do not affect their filtration effect and gas resistance,so they can be used as new bacteriostatic mask materials,while cotton cloth cannot be applied to new bacteriostatic mask materials because it is not waterproof and has high air resistance,but it has broad application prospects in bacteriostatic textiles.In summary,BC composite with bacteriostatic properties was successfully modified by microwave-assisted synthesis,which has good stability and has application value in bacteriostatic dressings,mask materials,protective clothing materials and bacteriostatic textiles.